This invention relates to semiconductor lasers, and in particular to transverse mode stabilized lasers with planar active layers.
One example of such a laser is described by T. Furuse et al in a paper entitled "Transverse Mode Stabilised AlGaAs BH laser having a Built-in Plano-convex Waveguide" presented at The Optical Communication Conference, Amsterdam, Sept. 17-19, 1979, 2.2-1 to 2.2-4. That paper discloses a construction in which a transverse waveguiding effect is provided for a planar active layer by the presence of an inverted rib of intermediate band gap material grown before the growth of the active layer. However, this structure has several disadvantages, especially as far as the smooth and proper epitaxial growth of the layers is concerned, because of the presence of the inverted rib on the substrate before the formation of the active layer.